Conventional cooling bases for a cooling composition include, for example, gels or aqueous solutions of crosslinked polyethylene glycol (PEG), polyethylene oxide (PEO), polyvinyl alcohol (PVA), sodium-carboxymethyl cellulose, polyacrylic acid, salts thereof, carboxyvinyl polymer (CVP) or the like.
The cooling composition is available in various forms such as a sheet having a cooling base sealed with a film of polyethylene, polypropylene or the like or a poultice comprising a non-woven fabric or like fabrics coated with a gel base. In recent years, a demand has been growing for poultice-type cooling products from the viewpoints of adhesion, fixation, convenience in use, heat-absorbing property and so on.
Generally the cooling base for use in such poultice-type cooling products are in the form of a gel which is superior in shape retentivity and adhesiveness. For this reason, it is very difficult to uniformly stir and knead the components of the cooling composition in the manufacture thereof. Because of this difficulty, there arise problems, for example, masses of components not dispersed well due to insufficient stirring and air bubbles incorporated into the gel base.
Attempts have been made in the art to overcome such problems using an organic solvent such as polyhydric alcohol in more than a specific amount to reduce the dispersion density of the base.
However, this method, although advantageous in giving a uniform gel composition, inevitably involves a decrease of water to be incorporated into the composition in an amount corresponding to the volume of the organic solvent, consequently failing to produce a cooling composition which can achieve a higher cooling effect.